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[T.m.f]

I can't think of anything in the transmission which could absorb a significant amount of engine output yet not destroy itself in the process. Certainly, if it was slipping, it would burn out the clutches in short order.

By all means do a fluid change, as that's advisable on a regular basis anyway, but don't count on it making much difference.

Sorry kev, are you agreeing that the loss of performance could be in the gearbox?

To be totally honest, as long as I have a reason for where the power has gone I am not fussed about getting a new gearbox to fix five tenths at the race track! But as a new car mechanic I like to understand it and have a definitive reason for it.

The facts are these. . . I have proved my engine is performing exactly as it should and did all those years ago. . . It has to be the tranny.

How to test this for sure. . . Transmission oil analysis! And yes, I am that sad 

How about changing the tranny for a ts model,best of both worlds then 

[Webby the Bear]

To be honest, I'm more interested in proving that it's the transmission slipping. How can I prove it's slipping SLIGHTLY? keep in mind it is only slight power loss so there's no obvious signs (e.g. hard to go in to gear) 

thoughts?

[Kevin Wood]

Sorry - what I meant to get across in my recent post is that even the slightest slip will turn into a complete failure in no time at all, so I don't think a slipping transmission is going to be limiting it.

Some fresh fluid might tighten up the torque converter a little, and will be good for it anyway, but aside from that, there is noting in the transmission that can reduce the acceleration without dying in spectacular style.

[Webby the Bear]

Got ya Kev. thanks for that.

So as ive proved the engine's spot on and the transmission wont affect acceleration (as ive done lots of testing and it hasn't blown up yet!) then I must conclude that its my testing (as opti and others pointed out before) or my driving is flawed.

so to prove this I need to go to santapod with a proper accelerometer (or hi-tec equivalent) and it should do it in the time. would folk concur?

[STEMO]

My question would be "Are you sure that the figures Vx originally released were accurate to the nearest tenth, or just a 'near enough' estimation"?

[Webby the Bear]

good question. but until I get an accurate time ''at the track'' with proper test equipment I know not if im near.

the worst thing would be to use this equipment and be a second or so over......then what does that mean! lol but until I get some actual results I cant say.

[Webby the Bear]

Ok, before we move on from the transmission.....

If it has any slip at all the transmission will lunch itself as per kev's post. BUT would any wear in the transmission cause power loss. I don't know if the sump has a magnet but I would expect after 15 years there would be metal shavings. . . As I've proved the engine hasn't worn and is working exactly right. . . Could this wear cause acceleration loss (wear as opposed to slip)

[Webby the Bear]

Here's summit I have just thought of 

Would manually shifting on the auto box from 1, 2, 3 and then in to 'D' improve the 0-60? I know when flooring it from a standstill it changes at around 50 - 55 (roughly) and I often think it would be better for acceleration if it could hold on before that change. And I wonder if that's how the testers do it?

Thoughts?

[Nick W]

Here's summit I have just thought of 

Would manually shifting on the auto box from 1, 2, 3 and then in to 'D' improve the 0-60? I know when flooring it from a standstill it changes at around 50 - 55 (roughly) and I often think it would be better for acceleration if it could hold on before that change. And I wonder if that's how the testers do it?

Thoughts?

Moving the gearlever won't make it physically change gear any quicker than letting it decide for itself.

[Webby the Bear]

Here's summit I have just thought of 

Would manually shifting on the auto box from 1, 2, 3 and then in to 'D' improve the 0-60? I know when flooring it from a standstill it changes at around 50 - 55 (roughly) and I often think it would be better for acceleration if it could hold on before that change. And I wonder if that's how the testers do it?

Thoughts?

Moving the gearlever won't make it physically change gear any quicker than letting it decide for itself.

No, I appreciate that. But you can hold on to gears longer and avoid the change up just before hitting 60. Assuming your gear changes were good then this would reduce the time, no?

[Broomies Mate]

Webby, lock it in 1st and boot the 'dangle berries' off it.  It'll either (depending on software) change up properly, or reduce throttle to 70ish% to save the box.

I'm gonna guess it'll change up and drive normally.

[JamesV6CDX]

Webby, lock it in 1st and boot the 'dangle berries' off it.  It'll either (depending on software) change up properly, or reduce throttle to 70ish% to save the box.

I'm gonna guess it'll change up and drive normally.

if you lock my 5 series in 1st, it'll change up, if you floor it.

Omega, it'll stay in 1st, and bounce off the red line!!!

[Broomies Mate]

Webby, lock it in 1st and boot the 'dangle berries' off it.  It'll either (depending on software) change up properly, or reduce throttle to 70ish% to save the box.

I'm gonna guess it'll change up and drive normally.

if you lock my 5 series in 1st, it'll change up, if you floor it.

Omega, it'll stay in 1st, and bounce off the red line!!!

Really?  I know the FWD Vx boxes will just bounce off the limiter, but in my experience (I cant test it, I dont drive one anymore) the AR25/35 will change up.

The e39 (I'm going to guess it has the same tranny as yours James)..... Yes, when you knock the stick into 'Manual'...... a useless thing, same as on the Saab.  It changes up and down when it wants to anyway!

[Mr.OmegaMan]

Webby, lock it in 1st and boot the 'dangle berries' off it.  It'll either (depending on software) change up properly, or reduce throttle to 70ish% to save the box.

I'm gonna guess it'll change up and drive normally.

if you lock my 5 series in 1st, it'll change up, if you floor it.

Omega, it'll stay in 1st, and bounce off the red line!!!

Aye what James said  

If it's in 2nd it moves between 1 & 2 it doesn't stay in 2nd or if your in 3rd it'll move between 1,2,3 etc.

[Webby the Bear]

Ok, so shifting manually won't help then